MdePkg/Library/BaseLib/Ebc/Synchronization.c

   1 /** @file
   2   Implementation of synchronization functions on EBC.
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 /**
  16   Performs an atomic compare exchange operation on a 32-bit
  17   unsigned integer.
  18
  19   Performs an atomic compare exchange operation on the 32-bit
  20   unsigned integer specified by Value.  If Value is equal to
  21   CompareValue, then Value is set to ExchangeValue and
  22   CompareValue is returned.  If Value is not equal to
  23   CompareValue, then Value is returned. The compare exchange
  24   operation must be performed using MP safe mechanisms.
  25
  26   @param  Value         A pointer to the 32-bit value for the
  27                         compare exchange operation.
  28   @param  CompareValue  32-bit value used in compare operation.
  29   @param  ExchangeValue 32-bit value used in exchange operation.
  30
  31   @return The original *Value before exchange.
  32
  33 **/
  34 UINT32
  35 EFIAPI
  36 InternalSyncCompareExchange32 (
  37   IN      volatile UINT32           *Value,
  38   IN      UINT32                    CompareValue,
  39   IN      UINT32                    ExchangeValue
  40   )
  41 {
  42   return *Value != CompareValue ? *Value :
  43            ((*Value = ExchangeValue), CompareValue);
  44 }
  45
  46 /**
  47   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
  48
  49   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
  50   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
  51   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
  52   The compare exchange operation must be performed using MP safe mechanisms.
  53
  54   @param  Value         A pointer to the 64-bit value for the compare exchange
  55                         operation.
  56   @param  CompareValue  64-bit value used in compare operation.
  57   @param  ExchangeValue 64-bit value used in exchange operation.
  58
  59   @return The original *Value before exchange.
  60
  61 **/
  62 UINT64
  63 EFIAPI
  64 InternalSyncCompareExchange64 (
  65   IN      volatile UINT64           *Value,
  66   IN      UINT64                    CompareValue,
  67   IN      UINT64                    ExchangeValue
  68   )
  69 {
  70   return *Value != CompareValue ? *Value :
  71            ((*Value = ExchangeValue), CompareValue);
  72 }
  73
  74 /**
  75   Performs an atomic increment of an 32-bit unsigned integer.
  76
  77   Performs an atomic increment of the 32-bit unsigned integer specified by
  78   Value and returns the incremented value. The increment operation must be
  79   performed using MP safe mechanisms. The state of the return value is not
  80   guaranteed to be MP safe.
  81
  82   @param  Value A pointer to the 32-bit value to increment.
  83
  84   @return The incremented value.
  85
  86 **/
  87 UINT32
  88 EFIAPI
  89 InternalSyncIncrement (
  90   IN      volatile UINT32           *Value
  91   )
  92 {
  93   return ++*Value;
  94 }
  95
  96 /**
  97   Performs an atomic decrement of an 32-bit unsigned integer.
  98
  99   Performs an atomic decrement of the 32-bit unsigned integer specified by
 100   Value and returns the decrement value. The decrement operation must be
 101   performed using MP safe mechanisms. The state of the return value is not
 102   guaranteed to be MP safe.
 103
 104   @param  Value A pointer to the 32-bit value to decrement.
 105
 106   @return The decrement value.
 107
 108 **/
 109 UINT32
 110 EFIAPI
 111 InternalSyncDecrement (
 112   IN      volatile UINT32           *Value
 113   )
 114 {
 115   return --*Value;
 116 }